In July, 2000 bought new Z28 and I always used 92 oct. before they changed it to 91 oct. (in California). Soon after they changed the gas the pinging started at about 29k. I now have 46k. Dealer couldn't solve problem when it was still under warranty. GM told the dealership the pinging was normal. I know it isn't normal or good for the engine. Put 100 octane gas in and pinging went away instantly! Does anyone know what needs to be done to solve this problem? Can't afford $4.29 per gal. for 100 oct. race gas, but it did stop the pinging. Any clues???
I am a woman who loves her car and nobody seems to be able to help me. There is only 1 gas station out-of-town that sells 100 oct. This is the 3rd Camaro I've owned and I am so pissed-off at GM and the Dealer. Please Help!! Thanks

 

Welcome to the world of pinging LS1's. You're not alone so don't worry. It is true that GM claims that the pinging is normal. It even says in the owners manual that it will ping under acceleration and going up a hill. It's not good and you don't have to settle for it though. Your pinging MAY be caused by oil contamination in the combustion mixture through the PCV system. This seems to be the most common reason why these cars knock. The LS1's PCV system is a flawed design and commonly picks up way more oil than it should from the crankcase air and squirts it into the throttle body. This oil laced induction air can lower the octane effect of your gasoline, thus causing pinging unless you're using an unusually high octane fuel. It can also leave carbon deposits on your pistons and foul your plugs, also causing the motor to ping. There are *** loads of ways to correct the problem...some easier than others. The most common thing to do is to add fuel filters in the PCV tubing. The modification that I like the most is the SHM mod seen here:

http://www.fbody.com/members/stevenm...ML/pcv_mod.htm

It has detailed step by step directions on how to perform it. The only downside is that some people say it reduces too much vacuum from the crankcase ventilation and can lead to piston ring seal problems. I did it on my car and I am not worried about it though. If you're willing to spend the money you can convert to the LS6 PCV system. It's about $150 in parts and with a 2000 model motor it will require some grinding of material off the engine block. The LS6 Vette motor has an improved PCV system. Basically GM designed a fix to the problem all while maintaining that there never was a problem in the first place. Other things people have done is adding a contamination separator to the PCV. These things are designed to remove contamination from compressed airstreams and are used in medical applications a lot. They can also be fitted with drain tubes so changing filters wont be necessary.

All of the information above is provided that your pinging is being caused by oil contamination. Other causes could be a clogged fuel filter, bad fuel pump...crap like that. My car had a catalytic converter going out and it screwed up the O2 sensor's reading and made it lean out. I would suggest looking into the PCV though...it seems to be the most common cause. You'll probably need new spark plugs if you've gotten oil contamination. You also might want to look into doing the top end cleaner thing which requires pouring GM's top end cleaner into the spark plug holes and leaving it there for a few hours. You'll need to change your oil after this. Also reset the computer because the knock sensors will pull timing out when you ping. Do a search on it. Good luck...

 

Pinging is the premature detonation of the air fuel mixture for any reason. Most common causes are low octane, high temperature, timing, combustion chamber deposits, mixture too lean.

So there are a few simple things that can be done - lower the engine temperature - thermostat and fan adjustment, retartd the timing - PCM adjustment, adjust mixture - PCM adjustment. Find a shop in your area that knows these cars and they should be able to help you.

Hope this helps. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by DaddySS:
<strong> Pinging is the premature detonation of the air fuel mixture for any reason. Most common causes are low octane, high temperature, timing, combustion chamber deposits, mixture too lean.

So there are a few simple things that can be done - lower the engine temperature - thermostat and fan adjustment, retartd the timing - PCM adjustment, adjust mixture - PCM adjustment.

Hope this helps. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I agree with this except for the fact that it's important to remember that detonation can be caused by one stimulant and not by all potential stimulants as a whole. If you're pinging because you're running lean up top a change to a lower thermostat will not correct it, just like if you have excessive carbon buildup pulling timing is not the answer. It's important to find the root of the problem and not mask it by pulling timing or adding fuel. There should be no reason why a stock 2000 Z28 is pinging except if something is malfunctioning. Adding a lower thermostat or tuning the PCM might help but it would be at the expense of engine performance if the pinging was being caused by oil contamination. If everything is functioning correctly there is no reason why a stock LS1 should run with knock retard when all engine parameters are unaltered.

<img border="0" alt="[driving]" title="" src="graemlins/gr_driving3.gif" />

 

Even if there is one specific cause for the problem... running lean for example, doesn't mean the common fixes won't work. The cooling mods are an excellent cure all because they take away the excess heat the detonation thrives on and offers other benefits as well. I agree that it would be good to take away the root problem/cause, but that is not always possible/favorable.
I had detonation problems. I chose to cool the combustion chambers and incoming air to solve my situation. The root cause of mine was running slightly lean. I guess I could have paid a bunch of $$$$ for the software/gadgets to richen it, but the low buck cure worked and the car makes more power now as a benefit... Lean is mean.
Some fixes: (one may work, you may need them all depending on root cause/seriousness)
Free thermostat mod
Auto fan mod
TB bypass
FRA
(Those top ones did it for me as a combo)
More:
Top end cleaner
Water wetter
One step lower heat range plugs
PCV mod
I have forgotten some, but these are the most helpful.

DO NOT USE RACING FUEL!
Racing fuel contains lead. Lead will destroy expensive sensors and emission compontents.

Good luck
Dave

Btw: They are using the "it's normal" thing as an out to get you to go away. They want to put you off until your warranty expires. I worked at a Chevy dealership a while. Been there, done that, had it done to me.
You could go in with a rod hanging out the side of your block and they will try "it's normal" first. Then blame you. Then try the cheapest fix they can. So on... until you leave them alone.

 

100 octane is unleaded, so it's okay to use it, but it's not necessary, pinging could be many different things, it could be bad gas (low octane) bad cats, lean condition, oil in intake, etc... the best things to do are, 160* thermostat and fans set for a 160* thermostat via HPP3, predator or some sort of tuning,
a colder plug may help also such as a NGK TR6's some people use a MAFT to richen up the car, a cheap way is to reverse the MAF backwards which will richen up the car, try that and see what happens, <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> it really works. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

 

That's cool. I have never seen unleaded racing fuel.
You can put a $20 automatic switch in the car to cut the fans on at a lower temp.
I'm not sure, but I don't think TR6s are lower heat range. I was told they are just different gap.
Ditto on turning the MAF backwards! I did that while I was sorting out my detonation. Worked fine. Just a little rich.
Dave

Some links:
http://ls1info.com/article.php?sid=180
http://ls1info.com/article.php?sid=222

 

Thanks for all of the replies. But there is sooo.. much that could be causing the pinging, what do I do first? Knock Sensor was replaced first, because I insisted that Dealership fix the problem. They replaced it, said it looked like moisture got in it. But it still pings. I've changed fuel filter, changed from 91 Oct 76 gas to Chevron 91 with techron. I had injecters purged, I change the oil regulary. I use synthetic. I took it to a place called Speed Merchant they put it on the scan tool, said yeah it's pinging even when it's not under a heavy load. Plugs were fine, they just couldn't figure it out. They said all the #'s on the scan were right where they should be. That cost me $250. Shouldn't they have known what to do next? Thermostat, PCM adjustment, etc... How do you determine oil contamination? Instead, they referred me to another dealer. This dealer said they would do a borescope inspection. I thought for a minute something might get accomplished, but I really don't think they did anything except test drive my car for 6 miles, call GM and GM said "it's normal". That cost me $50.00. I asked him if they did the borescope inspection and he said yeah, everything looked good. No carbon. I really don't think they even did the borescope thing. Can anyone please tell me why it seems as though nobody is capable of fixing this car for me. There must be a process of elimination?? I am getting terrible gas mileage, and performance has slightly changed. It sounds like a diesel in the morning until is warms up. Just a reminder, I am a female with no mechanical experience. All I'm trying to do is take care of my car. Any advice for the mechanic I go to next?? What is the proper way to troubleshoot?? If something is malfunctioning, then why can't the scan tool tell you so?? Do I just have to try everything until I get lucky? Does using race gas 100 oct. really hurt the car. It makes it stop pinging. If the oct. stopped the ping, doesn't it help narrow down the problem? Thanks!!

 

In order for us top provide more detailed guidance we will need to know a little more about the problem:

When did the problem start, was anything changed, added, fixed around the time that it started?

When does the pinging occur - when it is cold, when it warms up? In hot weather, with the A/C on? Does it occur more after you have been driving a while?

When they did the scan, what did they say the total advance was? Did it show any knock retard?

What did the scan say the air/fuel mixture was?

Does the car idle smoothly?

Where is the temperature guage during normal operation, does it stay above or below the 210 mark normally?

What else can you tell us about when you first noticed the problem and when it occurs?

 

This is not that hard of a problem to fix.

First, a couple of misconceptions in this thread...

"DO NOT USE RACING FUEL!
Racing fuel contains lead. Lead will destroy expensive sensors and emission compontents."

There are MANY types of unleaded racing fuel. VP Racing fuels alone makes 9 different kinds.

"I'm not sure, but I don't think TR6s are lower heat range. I was told they are just different gap."

You were told wrong. TR-5s (pre-gapped at .039)and TR-55s (pre-gapped at .059) are the same heat range as stock. TR-6s are pre-gapped at .039 and are cooler than stock. They are what most of the nitrous junkies around here use.

If the problem isn't from excessive oil consumption then there are a few different things that will help.

A 160 thermostat with fan settings to match.

TR-6 plugs (will have to be changed more often.) Even a new set of the stock heat range can often help if the old plugs were worn.

Richening the mixture (Easy to do WITHOUT PCM changing. Get a MAFT. Many of our sponsors sell them. You can change the mixture with a turn of a ****.) Here's one you don't hear everyday. Try flipping the MAF sensor around backwards. It'll richen the mixture up just a little bit. Sounds crazy but it works and it won't hurt a thing.

Getting rid of the cats (I know, not an option for you since you live in California.)

 

BTW, I'm going to move this to Computer Diagnostics and Tuning... <img border="0" alt="[burn out]" title="" src="graemlins/gr_burnout.gif" />